Looper operating mechanism for sewing machines



June 7, 3 F. LUTZ 1,861,540

LOOPER OPERATING MECHANISM FOR SEWING MACHINES Filed Sept. 18. 1929 2 Sheets-Sheet l June 7, 1932. F, LUTZ 1,861,540

LOOPER OPERATING MECHANISM FOR SEWING MACHINES Filed Sept. 18, 1929 2 Sheets-Sheet 2 cross shaft. eccentric on the mam shaft which cooperates Patented ilune 7, 1932 UNITED STATES PATENT OFFICE FRIEDRICH LUTZ, F STUTTGART, GERMANY, ASSIGNOR TO UNION SPECIAL MASCHINENFABRIK, G. M. B. 3., OF STUTTGART, GERMANY LOOPER OPERATING MECHANISM FOR SEWING- MACHINES Application filed September 18, 1929, Serial No. 393,528, and in Germany December 27, 1928.

The invention relates to new and useful improvements in a looper operating mechanism for sewing machines, and more particularly to a mechanism for operating the loopers of an overedge stitching machine.

An object of the invention is to provide a mechanism for operating the loopers in an overedge stitching machine wherein the movements imparted to the loopers are derived from independent trains of mechanism which have a common supporting means therefor.

In the drawings Figure 1 is a view partly in section and partly in front elevation showing the essential parts of a looper operating mechanism for an overedge stitching machine embodying the improvements.

Fig. 2 is a view partly in plan and partly in section of the same.

The invention is directed to a looper operat ing mechanism for an overedge stitching machine. The machine includes a needle, a looper cooperating with the needle beneath the work support and mounted beneath the on the main actuating shaft which is located beneath the work support and extends longitudinally of the bed of the machine.

The eccentric cooperates with an eccentric strap connected to a ball stud on a yoke fixed to the shaft. The under thread carrying looper is oscillated by a link connection to an arm attached to a yoke mounted on said cross shaft so as to oscillate freely on the This yoke is oscillated by an with an eccentric strap attached to a ball stud carried by the yoke. The cross shaft is mounted in suitable bearings carried by the bed of the machine. Thus it is that the 0 lo 'iers are operated by independent trains of devices which, however, are mounted in common supporting bearings.

Referring more in detail to the drawings, the machine includes a supporting bed 1 carrying an overhanging arm 2 of the usual construction. At the free end of the overhanging arm 2 is a needle head 3 in which a needle bar carrying a needle 4 reciprocates. Mounted on the bed is a work support 5. The material is held on the work support by a presser foot 6 and is fed across the work support by the usual feeding mechanislrrnot shown. Cooperating with the needle beneath the work support is a looper 7 which is fixed to a loopercarrier 8 pivoted at 9 to a suitable bearing 10 mounted on the bed 1 of the machine.

Located beneath the work support is the main actuating shaft 11 which is provided with a crank 12, and a link 13 cooperating with the crank reciprocates the needle. The shaft 11 is mounted beneath the work support 5 and extends lengthwise of the bed. The

shaft is rotated by a belt wheel 14. A cross shaft 15 is mounted in bearings 16, 16 carried by the bed.

Mounted on the cross shaft is a yoke member 17. Said yoke member 17 is provided with sleeves 18, 18 which are mounted on the shaft 15 for free oscillation thereon. The sleeves are close to the bearings 16, 16 and this prevents endwise movement of the yoke on the shaft. The sleeves are provided with suitable oil holes whereby the bearings of the yoke may be properly lubricated. Fixed to one of the sleeves 18 is an arm 19. The arm 19 has a slot 20 at the end thereof and a ball stud 21 is mounted in said slot for adjustment therein. The looper carrier 8 is also provided with a slot 22 in which a ball stud 23 is adjustably mounted. A link 24 cooperates with the ball studs 21 and 28 and thus connects the arm 19 to the looper carrier 8.

The yoke 17 is oscillated by means of an eccentric 25. This eccentric 25 is mounted on the main shaft 11. Cooperating with the eccentric 25 is an eccentric strap 26. The yoke 17 carries a ball stud 27 and the eccentric strap is attached to this ball stud. As the main shaft rotates it will through this eccentric impart oscillations to the yoke 17 and the yoke 17 through the arm 19 and link 24 will impart oscillations to the under thread carrying looper.

Cooperating with the looper 7 beneath the work support and with the needle 4 above the work support is an overedge loop-er 28. This overedge looper 28 is mounted in a looper carrier 29 fixed to a shaft 30 mounted for oscillation in a bearing 31 carried by the bed 1 of the machine. Attached to the shaft 30 is a sleeve having a depending arm carrying a ball stud 32. A link 33 is connected to this ball stud at one end and at its other end is connected to a ball stud 3% carried by an arm 35 which is fixed to a sleeve 36, and the sleeve, 36 is rigidly secured .to the cross shaft 15. Rigidly mounted on the cross shaft 15 between the sleeves 18, 18 is a yokemember 37 provided with a ball stud 38. An eccentric strap 39 is attached to this ball stud and cooperates with an eccentric 40 on the main shaft 11. As the main shaft rotates it will through this yoke member 37 impart an oscillation to the cross shaft 15 and the cross shaft 15 through the arm 35 and link 33 will impart oscillations to the overedge looper.

Thus it is that there is a train of mechanism from the eccentric 40 to the overedge looper which oscillates the looper and also a train of mechanism which is independent thereof from the eccentric 25 to the under thread carrying looper which oscillates the same. These trains of mechanism have a common bearing support. By making the trains of mechanism independent the timing of the operation of the loopers may be independently adjusted. As clearly shown in Fig. 2 the eccentrics are set at substantially ninety degrees to each other so that the loopers do not move in synchronism but are actuated in proper timing to bring about the cooperation of the stitch forming elements necessary to form the overedge stitches.

The shaft 15 is mounted in the bearings 16, 16 and the yoke 17 is mounted on the shaft 15 for bearing support. Thus it is that the yoke 17 is in reality mounted for support on the bearings 16. 16. The yoke 37 substantially fills the space between the sleeves 18, 18 and thus prevents en dwise movement of the shaft 15.

By the arrangement above described a machine has been provided wherein the parts for operating the two loopers of an overcdge stitching machine are comparatively few and may be readily placed in the small space available between the cloth plate and the bed. The only brackets necessary on the bed for the looper mechanism are the. two bearing supports 16, 16 for the shaft 15 and the two bearings support 10 and 31 for the loopers respectively.

It is obvious that minor changes in the debed, a cross shaft mounted in said earings, 4

means for oscillating said cross shaft from said actuating shaft, a yoke mounted for free oscillating movement on said shaft between said supporting bearings, means for oscillating said yoke fromsaid actuating shaft, an under looper, an overedge looper, devices for connecting one of said loopers to said yoke, and devices for connecting the other looper to said cross shaft.

2. The combination of a supporting bed, a work support carried thereby, a main actuating shaft between the bed and work support, bearings carried by said supporting bed, a cross shaft mounted in said bearings, means for oscillating said cross shaft from said actuating shaft, a yoke mounted for free oscillating movement on said shaft between said supporting bearings, means for oscillating said yoke from said actuating shaft, an under looper, an arm carried by said yoke, a link connecting said arm to said looper for oscillating the same, an overedge looper, an arm carried by said cross shaft, and a link connecting said arm to said overedge looper.

3. The combination of a supporting bed, a work support carried thereby, a main actuating shaft between the bed and work support, bearings carried by said supporting bed, a cross shaft mounted in said bearings, means for oscillating said cross shaft from said actuating shaft, a yoke mounted for free oscillating movement on said shaft between said supporting bearings, means for oscillating said yoke from said actuating shaft, a bearing carried by the bed, a looper carrier mounted in said bearing and provided with a looper cooperating with the needle beneath the work support, an arm carried by the yoke, a link connecting said arm to said carrier, and an overedge looper actuated from said cross shaft.

4. The combination of a supporting bed, a work support carried thereby, a main actuating shaft between the bed and work support, bearings carried by said supporting bed, a cross shaft mounted in said bearings, means for oscillating said cross shaft from said actuating shaft, a yoke mounted for free oscillating movement on said shaft between said supporting bearings, means for oscillating said yoke from said actuating shaft, a bearing carried by the bed, a looper carrier mounted in said bearing and provided with a looper cooperating with the needle beneath the work support, an arm carried by the yoke, a link connecting said arm to said carrier, a second bearing mounted on said supporting bed, a looper carrier mounted therein and provided with a looper cooperating with the needle above the work support, an arm carried by said cross shaft, and a link connecting said arm to said lastnamed looper carrier for oscillatingthe overedge looper.

5. The combination of a work support, a looper carrier therefor mounted beneath the work support, an overedge looper, a looper carrier therefor mounted beneath the work support, a main actuating shaft located beneath the work support, an actuated shaft .located beneath the work support, bearings for said shaft, means connected to the main actuating shaft for oscillating said actuated shaft, means operated by said actuated shaft for oscillating one of said looper carriers, a device freely mounted on said actuated shaft and connected to the other looper carrier for oscillating the same, and means actuated by said main shaft for oscillating said device on the actuated shaft.

6. The combination of a work support, a looper carrier therefor mounted beneath the work support, an overedge looper, a carrier therefor mounted beneath the work support, a main actuating shaft located beneath the work support, a cross shaft located beneath the work support, devices carried by the cross shaft and connected to one of said looper carriers for oscillating the same, means actuated by said main actuating shaft for oscillating said cross shaft, a yoke mounted on said cross shaft, means carried by said yoke and connected to the other carrier for oscillating the same, and means actuated by the main shaft and connected to said yoke for oscillating said yoke.

In testimony whereof. I affix my signature.

FRIEDRICH LUTZ. 

